磨损对套管特殊螺纹强度及密封性能的影响

Influence of Wear on Strength and Sealing Performance of Casing Premium Thread

套管螺纹接头磨损是影响套管柱密封和结构完整性的重要原因之一。由于套管螺纹接头结构特点复杂,目前对套管螺纹接头在磨损工况下的力学性能研究较少。建立TPCQ套管特殊螺纹的有限元模型,分析内压、外压作用下磨损套管螺纹接头的应力分布和密封性能。结果表明:螺纹剩余强度随着磨损深度的增加而降低;当磨损深度达到4 mm时,抗内压强度、抗外挤强度和抗拉强度分别下降了22.9%、26.1%和18.2%,此时密封性能参数小于临界密封性参数,螺纹密封有泄漏风险。提出的方法可以量化评价磨损后套管螺纹接头的剩余强度及密封性能,为套管剩余强度评估和套管强度校核提供理论基础和技术依据。

The wear of casing threaded joints is one of the important reasons affecting the sealing and structural integrity of casing strings.Due to the complex structure of casing threaded joints,there are few studies on the mechanical properties of casing threaded joints under wear conditions.The finite element model of the special thread of TPCQ was established,and the stress distribution and sealing performance of the worn casing threaded joint under the action of internal pressure and external pressure were analyzed.The results show that the residual strength of the thread decreases with the increase of the wear depth.When the wear depth reaches 4 mm,the burst strength,collapse strength and tensile strength decrease by 22.9%,26.1%and 18.2%,respectively,and the sealing performance parameter is less than the critical sealing index,so there is a risk of leakage in the threaded seal.The proposed method can quantitatively evaluate the residual strength and sealing performance of casing threaded joints,which provides a theoretical basis and technical basis for the evaluation and verification of casing residual strength.